Factors Affecting the Ability to Sustain Maximal Work

Purpose: The purpose of this investigation was to examine the ability to sustain a maximal running effort. Furthermore, the effects of aerobic fitness level, gender, anaerobic capacity, efficiency of energy production and utilization, and lactate threshold on maximal performance were examined. Methods: Maximal oxygen consumption (VO2max), ventilatory threshold (VT) and anaerobic capacity (AC) were determined for 22 subjects. Subjects then performed a treadmill test to exhaustion to determine the time spent at VO2max, time spent at the velocity (run speed) associated with 100% VO2max (vVO2max), and the time it took to reach VO2max at vVO2max. Statistical analysis included one-way ANOVA by gender, VO2max, gender/VO2max and VO2max/AC. Tukey's post-hoc tests were done to determine location of significance. Pearson product-moment correlations were performed between physiologic variables [VO2max, AC, VT, gross efficiency (GE) and net efficiency (NE)] and maximal run performance (time spent at VO2max and vVO2max, and time to reach VO2max). Results: Average time spent at VO2max was 0.79±0.13 minutes and time spent at vVO2max was 2.36±0.20 minutes. No differences in maximal run performance were observed between high fit (HF) and low fit (LF) groups; however, females spent significantly longer time at VO2max and vVO2max compared with males (p Conclusions: VO2max does not appear to be directly related with the ability to sustain a maximal run performance, while females spent a longer time at VO2max and vVO2max than males. GE and NE showed a moderately positive relationship with time at vVO2max and time to reach VO2max.